Atmospheric pressure gas glow discharge

ABSTRACT

A method and apparatus for glow discharge at pressures of atmospheric and above stabilized between two electrodes spaced apart greater than 3 mm by a swirling gas path. The passage of a reactant gas in the swirling gas stream may be utilized for highly efficient chemical reactions and heating of the gas stream. The simple and compact apparatus for atmospheric pressure glow discharge is suitable for chemical conversion of hydrocarbon gases into higher molecular weight products of greater value, for pretreating combustible hydrocarbon gases for enhanced combustion and for production of intense white light.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a process and apparatus for gas glowdischarge, particularly hydrocarbon gas glow discharges at aboutatmospheric pressure with high conversion of methane to acetylene andefficient conversion of electrical energy into chemical conversions.This process may be used for high efficiency transfer of energy in theconduct of chemical reactions, such as a pretreatment for hydrocarbongases, such as natural gas, to provide increased flame radiation andstability upon combustion. The hydrocarbon gas glow discharge accordingto this invention provides a high intensity white light and high volumelight source. The glow discharge according to this invention may also beused to activate non-hydrocarbon gases, such as hydrogen, nitrogen,oxygen, ammonia, or silanes in molecular form to produce thecorresponding atoms, ions, or excited species, such as free radicals.

2. Description of Related Art

Low pressure gas glow discharges and apparatus for their production areknown from a number of U.S. Patent, for example U.S. Pat. Nos.2,787,730; 3,018,409; 3,035,205; 3,423,562; 4,830,492; 4,963,792; and4,967,118. Glow discharge starters are known, for example, from U.S.Pat. Nos. 3,681,639 and 4,970,425.

Glow discharges are usually operable at subatmospheric pressure,typically less than about 20 Torr. When the pressure is increased, theglow discharge becomes an arc discharge. The two types of discharge aredistinguished by their electrical characteristics and their mode ofoperation. A glow discharge operates at high voltage and low currents,while an arc discharge operates at low voltage and high currents. As thecurrent is increased for a glow discharge, the discharge tends to covermore and more of the available cathode area until at some point thecurrent density exceeds a critical value and the discharge suddenlybecomes an arc. When this occurs, there is an abrupt drop in voltage andan increase in current. In the glow discharge, electrons are produced inthe gas phase by ionization of neutral species by electrons acceleratedby the electric field; in the arc discharge, the electrons are producedby copious emission of electrons from a hot cathode. Generally, theelectrodes are not consumed in a glow discharge; while in an arcdischarge, the cathode is consumed and must be replaced frequently.

Atmospheric pressure glow discharges in hydrogen have been described byBerman, C. H., Calcote, H. F. and Gill, R. J., Supersonic CombustionEnhancement by a Nonequilibrium Plasma Jet, Contract No. NAS1-18404,Final Report, AeroChem TP-467, (August 1987) and in air and hydrogen byFan, H. Y., The Transition from Glow to Arc, Phys.Rev., 55, 769, (1939).In both of these cases, the electrode separation was very small, in theorder of 1 mm. The observed discharges were identified as glowdischarges because of the voltage/current relationship. However, in anormal glow discharge, the electrode spacing can be increased byincreasing the applied voltage. In the above examples, this led to anarc discharge, so it may in fact be questioned as to whether a true glowdischarge was observed.

Swirl has been used to stabilize arc discharges by moving the arc overthe electrodes so they will not overheat or to spread the arc throughgas flowing through the device. Jahn, Robert J., Physics of ElectricPropulsion, pgs. 116-121, 140-141, McGraw-Hill Series in Missile andSpace Technology, McGraw-Hill Book Company, New York, N.Y., (1968).

High power glow discharge lasers and apparatus for their production areknown from a number of U.S. Patents, for example U.S. Pat. Nos.3,623,145; 3,704,428; 3,781,713; 3,982,209; 4,031,428; 4,335,462; and4,604,752.

Production of acetylene from hydrocarbons by various methods is known:U.S. Pat. No. 2,719,184 teaching incomplete combustion with oxygen in aflame reaction; U.S. Pat. No 2,799,640 teaching catalyzation by sparkdischarge; and U.S. Pat. No. 3,483,107 teaching utilization of radiofrequency plasma jets. Laboratory scale electrical discharge conversionof methane to acetylene using a small spacing between electrodes andoperated with very low flow rates has been described in Wiener, Ho andBurton, M., Decomposition of Methane in an Electrical Discharge, J. Am.Chem. Soc., 75, 5815 (1953). Recycle of processed gases through anelectrical discharge in the conversion of natural gas to acetylene hasbeen described in Schoch, E. P., et al, Acetylene from Hydrocarbons,University of Texas Publication No. 5011, (June 1950) and Pettyjohn, E.S., German Use of Natural Gas, A.G.A. Natl. Gas Dept. Proc., 33, (1946).

SUMMARY OF THE INVENTION

Glow discharges have many advantages over electric arcs for chemicalconversions. Glow discharges do not consume the electrodes as do arcs.Glow discharges provide much higher energy efficiencies than arcs sinceglow discharges are nonequilibrium devices operated at much lowertemperatures with ionization produced by electric field acceleration ofelectrons rather than by thermal ionization, thereby consuming much lessheat capacity energy and greatly reducing energy loss due to radiation.Further, glow discharge devices are much simpler and more compact thanarc discharge devices making the glow discharge devices much morereadily integrated into associated apparatus.

Glow discharges normally have been considered low pressure discharges,operated at pressures of less than about 20 Torr. As the pressure isincreased, the prior glow discharges have become a spark or arc. Priornonequilibrium glow discharges have been limited due to the necessity ofthe electrodes being spaced no further apart than about 1 mm to maintaina stable glow discharge as atmospheric pressure is approached. Thisclose electrode spacing limits the volume of the glow discharge and,thus, the flow volume of gas which may be treated in the glow discharge.The requirement for operation at subatmospheric vacuum pressures toobtain greater electrode spacing is not desirable due to the requirementof a substantial vacuum pump and of an enclosed subatmospheric pressurechamber and process gas pressure control.

It is an object of this invention to provide a method and apparatus forstable glow discharges at higher pressures than previously operable.

It is another object of this invention to provide a method and apparatusfor high gas flow stable glow discharges at about atmospheric pressure.

Yet another object of this invention is to provide a method andapparatus for stable glow discharges at greater electrode spacings andat higher pressures than previously operable.

It is still another object of this invention to provide a method andapparatus for conducting chemical reactions by passing reactant gas orvapor through a glow discharge and transferring energy from the glowdischarge to the reactant gas forming product gas.

It is an object of this invention to provide a method and apparatus forpretreating combustible hydrocarbon gas or vapor to produce highermolecular weight hydrocarbons, carbon soot and hydrogen by passinghydrocarbon gas, such as methane or natural gas, through a glowdischarge at higher volume flow and higher pressure than prior glowdischarges.

Still another object of this invention is to provide a method andapparatus for conduct of reactions of reactant gases, such as hydrogen,nitrogen and oxygen in molecular form to produce the correspondingatoms, ions or excited species.

Yet another object of this invention to provide a method and apparatusfor conversion of gaseous molecules into reactive atoms and freeradicals, such as NH₃ to produce N. and NH₂. and silane to produceSi_(x). and H..

It is another object of this invention to provide a method and apparatusfor creating an intense white light by passing hydrocarbon gas, such asmethane or natural gas, through a glow discharge at higher pressure thanprior glow discharges.

These and other objects and advantages of the invention are achieved bypassing gas or vapor in a swirling pathway to form a vortex between twoopposing electrodes within a glow discharge chamber, a first of theelectrodes having an electric potential with respect to the second ofthe electrodes sufficiently different to maintain a glow dischargebetween the electrodes, and passing the gas or vapor through an exitport from the discharge chamber in or near one of the electrodes at thedownstream end of the vortex. The swirling gas stabilizes the glowdischarge permitting separation of the electrodes to distances of morethan about 3 mm apart and operation of the glow discharge at pressuresof up to several atmospheres. Greater separation of the electrodesallows much higher flow volumes of reactant gas to pass through a muchlarger glow discharge volume providing higher energy transfer forefficient conduct of chemical reactions, such as conversion ofhydrocarbon gas to higher hydrocarbons, carbon and hydrogen. Operationof these types of glow discharges at higher pressures, such asatmospheric, greatly reduces energy and design requirements of thesystem. The small size, operation at about atmospheric pressure, andsimplicity of operation of the apparatus of this invention permits itsfacile incorporation into other chemical systems and processes, such aspretreatment of combustible hydrocarbon gases in close association witha burner for enhancement of combustion, as a source of injection gasesfor spark ignition engines, or as a source of reactive gas, such ashydrogen, nitrogen or oxygen atoms obtained from the correspondingmolecular gases to be used as chemical reactants.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further objects and advantages of this invention willbecome apparent upon reading the description of =specific preferredembodiments with reference to the drawings, wherein:

FIG. 1 is a cross-sectional view of one embodiment of a atmosphericpressure gas glow discharge chamber according to this invention;

FIG. 2 is a plot of discharge voltage versus discharge current with theflow of air and natural gas through the glow discharge chamber shown inFIG. 1; and

FIG. 3 is a cross sectional view of another embodiment of an atmosphericpressure gas glow discharge chamber according to this invention suitablefor pretreatment of combustible gases.

DESCRIPTION OF PREFERRED EMBODIMENTS

The glow discharge according to this invention is generally conductedbetween two opposing electrodes within a glow discharge chamber. By theterminology chamber, as used in this description and claims, we do notmean to be limited to a closed chamber. Since the glow discharge may beoperated at atmospheric pressures, there is not the requirement of aphysical chamber for maintenance of very low subatmospheric pressures.When operating at about atmospheric pressures, chamber walls may haveopenings for passage of light created by the glow discharge, or thechamber may be created and defined by swirling gas without therequirement of physical walls. To aid in gas flow, at least somephysical definition of a chamber is usually present, but it is a featureof this invention that a large portion of the chamber may be open to theatmosphere.

The electrodes may be of any suitable material as known to the art andmay be cooled, if desired, by any means known to the art, such as bywater flow. Copper and brass are suitable electrode materials due totheir high electrical conductivity and heat transfer coefficients. Theelectrodes may be a wide variety of shapes and each electrode may be ofa different shape, as will be specifically exemplified below. Anelectrode may be shaped as a flat disc, a partial cone, a wire, asphere, and the like, and may define a gas entry port or a gas exitport. One of the electrodes is maintained at a higher positiveelectrical potential than the other electrode, the potentialdifferential being sufficient to maintain a glow discharge between theelectrodes. The potential differential is generally in the order ofkilovolts, about 1 to about 5 kilovolts, but may be as low as 200 volts.A potential is applied between two electrodes and one of the electrodesmay be maintained at ground for safety reasons by means known to theart.

The glow discharge may be initiated by any suitable means known in theart. With the electrodes separated the desired distance for use in thisinvention, ignition may be achieved by using a vacuum pump to reduce thepressure to the point where ignition occurs easily and then raising thepressure to the desired operating pressure. The glow discharge may beinitiated by igniting a low pressure air or nitrogen discharge, at lessthan about 0.1 atmosphere, and then adding the desired reactant gas andincreasing the pressure to the desired pressure with flow of reactantgas and turning off the nitrogen flow. It is not necessary to have aflowing system or to use any particular gas for this type of ignition.The reduced pressure may be attained by a small mechanical pump whenthere is no flow through the system by reducing the pressure in a largevolume and then connecting the large low pressure volume to thedischarge chamber. The glow discharge may also be ignited by having amovable electrode reduce the electrode distance for ignition and thenreturn to the desired operating distance. This may also be achieved byhaving a separate ignition electrode. A supplementary electrical supplymay also be used to aid in ignition.

An important feature of this invention is the passage of gas or vapor ina swirling pathway between the two electrodes and passing the gasthrough an exit port in or near one of the electrodes, thereby forming avortex of the swirling gas through the glow discharge between theelectrodes and having its downstream end at or near the exit port.Introduction of the gas in a tangential or swirling manner in the regionof the electrode opposing the exit port combined with the flowing exitof gas from the exit port creates the desired vortex of the swirlinggas. The radially inward component of the swirling gas approaching theexit port also aids in the stability of the glow discharge by keepingthe discharge centered, particularly between electrodes spaced more thanabout 3 mm apart, especially those spaced about 5 to about 25 mm apart.Without such flow, the discharge tends to drift to the edge of theelectrode. Stability may also be improved by a ring, or otherappropriate structure on the electrode opposing the gas exit port to aidin attachment of the base of the glow discharge to that electrode. Whilea stable glow discharge could be maintained for gas flow entering andexiting through opposed electrode gas ports, a much higher gas flow ratemay be maintained with gas entering through tangential swirl tubes. Gasflow velocities of about 10 to about 50 meters per second (STP) aresuitable. The greater spacing of electrodes makes the requirements fortheir being parallel, which has been a problem in previous closelyspaced electrode glow discharges, much less critical. The gas swirlmoves the point of heating on an electrode surface to aid in preventingarcing. The swirling gas also provides enhanced energy transfer forchemical reaction in passage through the glow discharge. We observedthat, except at the low pressures used to initiate the glow discharge,the swirling gas always tended to form a narrow cylindrical type volume,which is typical of high pressure discharges. Therefore, the only mannerin which the discharge volume could be increased was by making it longerby increasing the electrode spacing. The larger discharge volume is alsoadvantageous due to the increased amounts of electric power which can bedelivered to the discharge.

The larger electrode spacing and the enhanced energy transfer effectedby the swirling gas action according to this invention makes possiblemuch larger gas flows through the glow discharge for chemical reaction.Flow rates of about 4 to about 15 liters per minute were found to bepractical with a chamber of 10 ml volume and an exit port of 4 mmdiameter. A wide variety of chemical reactions utilizing energy from aglow discharge may be conducted by passage of gas through the glowdischarge according to this invention. For example, hydrocarbon gas,selected from methane, ethane, propane and natural gas, which have beenparticularly recalcitrant to reaction, may be converted to more valuablecompounds by the method of this invention. We have found, withelectrodes 10 mm apart, high conversion of methane to acetylene,obtaining forty percent of the maximum possible conversion. We have alsofound high efficiency utilization of electrical energy into chemicalchange, in the order of over fifty percent. Non-hydrocarbon gases may beactivated in a similar manner by passage through the glow discharge ofthis invention. Diatomic molecules, such as hydrogen, nitrogen andoxygen may be converted to the corresponding atoms, ions or excitedspecies, and polyatomic molecules, such as ammonia and silane may beconverted into reactive atoms and free radicals, such as NH₃ to produceN. and NH₂. and SiH₄ to produce Si_(x). and H..

The high conversion of methane to acetylene makes the process of thisinvention very attractive for pretreating hydrocarbon combustible gasesor vapor prior to combustion to form products comprising higherhydrocarbons, hydrogen and carbon soot. Combustion of these productssignificantly enhances radiant energy output of a burner, enhances flameluminosity, stabilizes the flame and increases burning velocity,resulting in increased throughput capability. Methane pyrolysis with thesupply of 45 kcal/mole methane results in hydrogen and acetylene withthe ratio of hydrogen:acetylene of 3:1 Thus, the maximum possibleconcentration of acetylene in the product gases with the completedecomposition of methane is 25 percent. Prior attempts in the conversionof methane to acetylene have resulted in direct carbon formation whichrequires only 17.89 kcal/mole of methane. For burner applications, it ismore desirable to form carbon in the flame from acetylene due to theease of transport of acetylene as compared to carbon. According to thepresent invention, formation of high amounts of acetylene and hydrogenwith some soot by pretreating combustible hydrocarbon gases at aboutatmospheric pressure provides an enhanced combustible gas for directcombustion. The atmospheric pressure gas glow discharge between widelyspaced electrodes also very efficiently heats the gas stream providingpreheated gas for combustion, utilizing much of the electrical energy tothe discharge. The electrical energy not consumed in activating thereactants or transferred to the chamber walls is deposited in the gas toheat it. Operation of the glow discharge at about 0.5 to about 10atmospheres, including atmospheric and higher pressures, and thesimplicity of the apparatus allows the glow discharge to be incorporatedinto a burner, eliminating problems of soot transport. FIG. 3schematically shows one embodiment of a suitable atmospheric glowdischarge device for incorporation into a burner. Chamber wall 31 iscylindrical in its lower portion surrounding electrode 33 and isconically shaped in its upper portion to fit electrode 32. Electrode 33is connected to DC power source 34, positive polarity, and electrode 32is connected to ground 35 to maintain the desired voltage between theelectrodes. Alternating current as well as direct current power can beused to sustain the glow discharges. Combustible gas is fed into theglow discharge chamber through swirl tubes 37 and 38, and additionalcombustible gas may be fed axially as shown by arrows 39. The gas passesin a swirling motion, shown by path 42, about and through glow discharge41 and exits through exit port 43 in the center of electrode 32 asproduct stream 40. One manner of incorporation into a burner is to havethe higher than atmospheric pressure glow discharge device shown in FIG.3 surrounded by an annular oxidizer or air flow chamber and to burn theproduct gas directly passing from exit port 43. The same apparatus, in asimilar manner, can provide reactive gases, such as hydrogen, nitrogenor oxygen atoms produced from the corresponding molecular gases passedthrough the glow discharge.

The method and apparatus of this invention may also be used to create anintense white light by passing hydrocarbon gas or vapor in the swirlingpathway between two electrodes. An intense white light is formed whenpassing pure hydrocarbon gas or smaller concentrations of about 3 toabout 60 percent in a carrier gas, such as nitrogen, through the glowdischarge. The greater separation distance of the electrodes provides alarger volume of the radiating source than previously obtainable. Thewhite light emission fills a significantly larger volume than thedischarge itself and it is believed that the formation of small sootparticles and their activation by the glow discharge renders themefficient radiators of the light. A luminous jet could also be formed bysoot particles leaving through the exit jet. The swirling gas patternalso aids in preventing soot buildup on transparent portions of the glowdischarge chamber. Operation of the glow discharge of the presentinvention at about atmospheric pressure also allows openings in the glowdischarge chamber for passage of the light, making the intense lightavailable for many uses. Operation of the glow discharge at 200 Wattswith a natural gas flow produced a white light of intensity far greaterthan a 200 Watt light bulb.

In the specific embodiment shown in FIG. 1, glow discharge chamber 10was formed with copper disc-shaped electrodes 12 and 13, 32 mm indiameter, spaced apart 10 mm by circular non-electrically conductingacrylic walls 11 with gas inlet swirl tubes 17 and 18. The electrodefaces were flat and each of the electrodes had a central port of 4 mminside diameter for introduction or outlet of gas. Ring 16 providedattachment for the base portion of the glow discharge to aid instabilization of the discharge and to prevent it from wandering over thesurface of electrode 12. Electrode 12 was connected to D.C. power supply14 (positive polarity). Electrode 13 was connected to ground 15. Gasinlet tube 19, in communication with the central inlet port in electrode14, was controlled by valve 20. Gas outlet tube 21, in communicationwith central exit port 26 in electrode 13, was controlled by valve 22.Vacuum tube 23, controlled by valve 24, provides communication with avacuum pump (Not shown). Gas sampling tube 25 provides communicationfrom gas outlet tube 21 to any desired chemical analysis apparatus foranalysis of product gases. Reaction gases can enter through gas inlettube 19 in electrode 12 with the same or different gas entering throughswirl tubes 17 and 18, such as a carrier gas through the swirl tubes.Reaction gases also can enter only through swirl tubes 17 and 18 withgas inlet tube 19 closed by valve 20. By this means, the swirl number, ameasure of extent of swirl, and the quantity of gases or vapor passingthrough the apparatus can be independently controlled.

Initiation of the discharge was easily accomplished in either air ornitrogen at pressures below about 0.1 atmosphere obtained by activatinga vacuum pump attached to vacuum tube 23 with valve 24 opened with theother valves closed. After ignition of the discharge, operation atatmospheric pressure was accomplished by steadily increasing the chamberpressure by closing valve 24 connecting the chamber to the vacuum pumpand then, as one atmosphere pressure was approached, opening valve 22which allowed discharge gases to vent to atmospheric pressure. Thechamber operated at a little over one atmosphere pressure due topressure losses in the gas outlet tube 21. When using hydrocarbon gas,such as methane or natural gas flows, a nitrogen discharge was firstinitiated, to avoid combustion in the chamber, which was brought up toatmospheric pressure prior to addition of the hydrocarbon gas. Thehydrocarbon gas to be reacted was then added to the chamber at steadilyincreasing rates and the nitrogen flow proportionately decreased untilit was turned off.

Using no flow of air at atmospheric pressure and an electrode separationof 1 mm, with one flat and one ported electrode, without ring 16, adischarge current and discharge voltage curve, as shown in FIG. 2,showed, typical for glow discharge, no change in voltage with increasinglow current up to about 1 Amp. with relatively high voltages in excessof 350 volts. Varying pressure between 100 and 760 Torr changed thedischarge voltage only slightly, but did reduce the maximum dischargecurrent with increasing pressure. Thus, it was clear that the dischargewas a glow, as compared to an arc, which is typically tens of ampereswith low voltages of about 10 to 20 volts.

The current-voltage curve for a swirl stabilized atmospheric pressurenitrogen glow discharge obtained in the apparatus shown in FIG. 1 withelectrode separation of 10 mm is shown in FIG. 2. The curves for air at1 mm electrode spacing and nitrogen at 10 mm electrode spacing arequalitatively similar with the maximum current for the nitrogen swirlstabilized discharge greatly increased. The corresponding curve for aswirl stabilized natural gas glow discharge conducted under the sameconditions is also shown in FIG. 2. This shows the rising portion of thecurve with the natural gas glow discharge producing the normal glowcurrent-voltage curve after the current exceeded 3.5 amperes. Themaximum electric power supplied was on the order of 2.3 kW.

Chemical conversion efficiencies were measured by injecting gas samplesinto a Hewlett-Packard Model 5830A gas chromatograph. Some conversion inM. G. Industries CP grade methane was observed prior to introduction ofmethane swirl into the chamber. Results on back to back samples ofproduct gas taken from swirl stabilized natural gas (Linde) glowdischarge conducted at atmospheric pressure between electrodes 10 mmapart showed the product gas contained 14.6 and 14.9 percent acetylene.Concentrations of acetylene, ethylene and ethane in the input naturalgas were found to be less than 0.8 percent by gas chromatography.Therefore, the acetylene in the product gas represented a conversion ofmore than 25 percent of the methane in the natural gas into acetylene.If only the case of methane conversion to acetylene and hydrogen isconsidered, the composition for the lower of the above two outputs is10% acetylene, 31% hydrogen and 59% methane which represents 40% of themaximum possible conversion concentration of 25% obtainable bystoichiometric considerations. Under more optimum conditions, the amountof methane conversion to acetylene may be higher. The lowerconcentration of acetylene is due to dilution with the hydrogenproduced. In these runs, the natural gas flow was 0.139 1/sec (8.31/min.) at 250 V and 3 A. The power input was about 1/3 of the maximumshown in FIG. 2. The 750 W of power consumed is consistent with thechemical equation for conversion of methane to acetylene and hydrogenand the measured acetylene concentrations at the above gas flow rate.Based on the 25 percent conversion of methane and an input of 750 W, thepower conversion to chemical change efficiency is slightly over 50percent. This shows the very high energy transfer in the atmosphericglow discharge between two electrodes spaced at 10 mm apart.

While in the foregoing specification this invention has been describedin relation to certain preferred embodiments thereof, and many detailshave been set forth for the purpose of illustration, it will be apparentto those skilled in the art that the invention is susceptible toadditional embodiments and that certain of the details described hereincan be varied considerably without departing from the basic principlesof the invention.

We claim:
 1. A method for gas glow discharge comprising; passing gas orvapor in a swirling pathway to form a vortex between a first and secondopposing electrodes within a glow discharge chamber, said firstelectrode having an electric potential with respect to said secondelectrode to maintain a glow discharge between said electrodes, andpassing gas or vapor from said vortex through an exit port from saiddischarge chamber in or near one of said electrodes.
 2. A method for gasglow discharge according to claim 1 wherein said gas is passed throughan exit port in a central portion of one of said electrodes.
 3. A methodfor gas glow discharge according to claim 1 wherein both said electrodesare flat.
 4. A method for gas glow discharge according to claim 1wherein said electrode opposing said exit port has a ring structurealigned with said exit port stabilizing said glow discharge.
 5. A methodfor gas glow discharge according to claim 1 wherein said gas in a lowerportion of said swirling gas pathway passes over a generally conicalshaped electrode opposing said exit port.
 6. A method for gas glowdischarge according to claim 1 wherein said opposing electrodes arespaced more than about 3 mm apart.
 7. A method for gas glow dischargeaccording to claim 1 wherein said opposing electrodes are spaced about 5to about 25 mm apart.
 8. A method for gas glow discharge according toclaim 1 wherein said gas is a hydrocarbon gas selected from the groupconsisting of methane, ethane, propane and natural gas.
 9. A method forgas glow discharge according to claim 1 wherein pressure within saidglow discharge chamber is maintained at about 0.5 to about 10atmospheres for maintaining said glow discharge.
 10. A method for gasglow discharge according to claim 1 wherein pressure within said glowdischarge chamber is maintained at about atmospheric for maintainingsaid glow discharge.
 11. A method for gas glow discharge according toclaim 1 wherein the gas flow through said glow discharge is about 10 toabout 50 meters per second (STP).
 12. A method for gas glow dischargeaccording to claim 1 wherein said gas is selected from the groupconsisting of molecular hydrogen, nitrogen, oxygen, ammonia and silane.13. A method for gas glow discharge according to claim 1 comprising theadditional steps; igniting said discharge at subatmospheric pressure andthen increasing pressure to a higher operating pressure while passinggas or vapor in a swirling pathway to form a vortex between said firstand second electrodes, said first electrode having an electric potentialwith respect to said second electrode to ignite, establish and maintaina glow discharge between said electrodes.
 14. A method for gas glowdischarge according to claim 13 wherein said subatmospheric pressure isless than about 0.1 atmosphere.
 15. A method for gas glow dischargeaccording to claim 1 comprising the additional steps; igniting saiddischarge at about atmospheric pressure by spacing said first and saidsecond opposing electrodes close together at an ignition position andapplying a voltage, then increasing the spacing between said electrodesto an operating position while passing gas or vapor in a swirlingpathway to form a vortex between said electrodes, said first electrodehaving an electric potential with respect to said second electrode toignite, establish and maintain a glow discharge between said electrodes.16. A method for gas glow discharge according to claim 1 comprising theadditional steps; igniting said discharge at about atmospheric pressureby spacing an ignition electrode close to said first electrode andapplying a voltage to said ignition electrode during an ignition stage,and applying an electric potential between said first and said secondelectrodes while passing gas or vapor in a swirling pathway to form avortex between said first and second electrodes to ignite, establish andmaintain a glow discharge between said first and second electrodes. 17.A method for gas glow discharge according to claim 1 comprising theadditional steps; igniting said discharge at about 0.5 to about 10atmospheres pressure by spacing an ignition electrode close to saidfirst electrode and applying a voltage to said ignition electrode duringan ignition stage, and applying an electric potential between said firstand said second electrodes while passing gas or vapor in a swirlingpathway to form a vortex between said first and second electrodes toignite, establish and maintain a glow discharge between said first andsecond electrodes.
 18. A method for conducting chemical reactionscomprising; passing reactant gas or vapor in a swirling pathway to forma vortex between two opposing electrodes spaced apart greater than about3 mm, a first of said electrodes having an electric potential withrespect to the second of said electrodes to maintain a glow dischargebetween said electrodes, transferring energy from said glow discharge tosaid reactant gas forming product gas, and passing said product gasthrough an exit port in or near one of said electrodes.
 19. A method forconducting chemical reactions according to claim 18 wherein saidreactant gas is a hydrocarbon gas selected from the group consisting ofmethane, ethane, propane and natural gas.
 20. A method for conductingchemical reactions according to claim 19 wherein at least about 25percent of the methane present in said reactant gas is converted toacetylene in said product gas.
 21. A method for conducting chemicalreactions according to claim 18 wherein said reactant gas is selectedfrom the group consisting of molecular hydrogen, nitrogen, oxygen,ammonia and silane which upon passage through said glow discharge isconverted to the corresponding atoms, ions or free radical activespecies.
 22. A method for conducting chemical reactions according toclaim 18 wherein pressure surrounding said glow discharge is maintainedat about 0.5 to about 10 atmospheres.
 23. A method for conductingchemical reactions according to claim 18 wherein pressure surroundingsaid glow discharge is maintained at about atmospheric.
 24. A method forconducting chemical reactions according to claim 18 wherein saidreactant gas flow through said glow discharge is about 10 to about 50meters per second (STP).
 25. A method for conducting chemical reactionsaccording to claim 18 wherein said opposing electrodes are spaced about5 to about 25 mm apart.
 26. A method for conducting chemical reactionsaccording to claim 18 wherein said product gas is passed through an exitport in a central portion of one of said electrodes.
 27. A method forconducting chemical reactions according to claim 18 wherein both saidelectrodes are flat.
 28. A method for conducting chemical reactionsaccording to claim 18 wherein said electrode opposing said exit port hasa ring structure aligned with said exit port stabilizing said glowdischarge.
 29. A method for conducting chemical reactions according toclaim 18 wherein said reactant gas in a lower portion of said swirlingpathway passes over a generally conical shaped electrode opposing saidexit port.
 30. A method for pretreating combustible hydrocarbon gases orvapor prior to combustion comprising; passing said hydrocarbon gases ina swirling pathway to form a vortex between two opposing electrodesspaced apart greater than about 3 mm, a first of said electrodes havingan electric potential with respect to the second of said electrodes tomaintain a glow discharge between said electrodes, transferring energyfrom said glow discharge to said hydrocarbon gases forming productscomprising higher hydrocarbons, hydrogen and carbon soot, and passingsaid products and unreacted hydrocarbon gases through an exit port in ornear one of said electrodes.
 31. A method for pretreating combustiblehydrocarbon gases according to claim 30 wherein said hydrocarbon gas isselected from the group consisting of methane, ethane, propane andnatural gas.
 32. A method for pretreating combustible hydrocarbon gasesaccording to claim 31 additionally comprising passing said products andunreacted hydrocarbon gases through said exit port directly into aburner nozzle.
 33. A method for pretreating combustible hydrocarbongases according to claim 30 wherein at least about 25 percent of themethane present in said hydrocarbon gases is converted to acetylene insaid products.
 34. A method for pretreating combustible hydrocarbongases according to claim 30 wherein pressure surrounding said glowdischarge is maintained at about 0.5 to about 10 atmospheres.
 35. Amethod for pretreating combustible hydrocarbon gases according to claim30 wherein pressure surrounding said glow discharge is maintained atabout atmospheric.
 36. A method for pretreating combustible hydrocarbongases according to claim 30 wherein said hydrocarbon gas flow throughsaid glow discharge is about 10 to about 50 meters per second (STP). 37.A method for pretreating combustible hydrocarbon gases according toclaim 30 wherein said opposing electrodes are about 5 to about 25 mmapart.
 38. A method for creating an intense white light comprising;passing gas comprising hydrocarbon gas or vapor in a swirling pathway toform a vortex between two opposing electrodes, a first of saidelectrodes having an electric potential with respect to the second ofsaid electrodes to maintain a glow discharge between said electrodes,and passing said gas through an exit port in or near one of saidelectrodes.
 39. A method for creating an intense white light accordingto claim 38 wherein said hydrocarbon gas is selected from the groupconsisting of methanes ethane, propane and natural gas.
 40. A method forcreating an intense white light according to claim 39 wherein saidhydrocarbon gas is present in a carrier gas in a concentration of about3 percent to about 60 percent.
 41. A method for creating an intensewhite light according to claim 38 wherein the pressure surrounding saidglow discharge is maintained at about 0.5 to about 10 atmospheres.
 42. Amethod for creating an intense white light according to claim 38 whereinpressure surrounding said glow discharge is maintained at aboutatmospheric.
 43. A method for creating an intense white light accordingto claim 38 wherein said gas flow through said glow discharge is about10 to about 50 meters per second (STP).
 44. A method for creating anintense white light according to claim 38 wherein said opposingelectrodes are about 5 to about 25 mm apart.